What is the primary treatment approach for SIADH?

• A. Fluid restriction and addressing underlying cause; careful correction of hyponatremia
• B. High-sodium diet
• C. Rapid hypertonic saline without restriction
• D. Increase fluid intake with diuretics

Answer: (A)

SIADH is treated mainly by limiting free water intake and identifying and addressing the underlying cause driving ADH excess. By restricting fluids, you reduce water retention and allow serum sodium to rise toward normal gradually, which is safer and more effective than trying to fix it with fluids or salt alone. At the same time, you work to remove or treat the trigger—such as a medication, infection, pulmonary disease, or a tumor—that is causing the excess ADH release.

If the hyponatremia is severe or causing dangerous symptoms, hypertonic saline can be used, but only with careful monitoring and usually alongside fluid restriction to control the rate of correction and avoid overshoot that could injure brain cells. The other options don’t address the root issue: a high-sodium diet doesn’t systematically correct the water imbalance, increasing fluids with diuretics can worsen hyponatremia, and rapid hypertonic saline without restriction risks rapid overcorrection.